A gigabit-capable passive optical network (GPON) system generally includes an optical line terminal (OLT) at a central office, an optical network unit (ONU) on a user side, and an optical distribution network (ODN), and uses a point-to-multipoint network structure. The ODN includes passive optical components, such as a single-mode optical fiber, an optical splitter, and an optical connector, and provides an optical transmission medium for a physical connection between the OLT and the ONU. According to different locations of an ONU in an access network, a GPON system may have several application types: fiber to the cabinet (FTTCab), fiber to the curb (FTTC), fiber to the building (FTTB), fiber to the home (FTTH), fiber to the business/office (FTTBiz/FTTO), and the like.
A diagram of protection switching networking of an existing GPON ONU is shown in FIG. 1. It should be noted that each ONU includes two uplink passive optical network (PON) interfaces, and the two interfaces are connected to two PON interfaces of an OLT by using different ODNs.
OLT: Both an active PON interface and a standby PON interface of an OLT are in a working state, the OLT needs ensure that service information of the active PON interface can be backed up to the standby PON interface in a synchronization manner, so that in a protection switching process, the standby PON interface can maintain that a service attribute of an ONU does not change.
Optical splitter: Two 1:N optical splitters are used.
ONU: Each ONU may separately use different PON MAC chips and different optical modules, and in a protection switching process of a PON interface, the ONU can maintain that a local service attribute does not change.
Both an active PON interface and a standby PON interface of an ONU are in a working state (that is, the ONU completes ONU registration, and standard and extended PLOAM message processing on two PON interfaces at the same time), and in a protection switching process of a PON interface, initialization configuration and service attribute configuration of the ONU do not need to be performed on the standby PON interface.
Both an ONU and an OLT detect a link status, and determine, according to the link status, whether to perform switching. If the OLT detects that an uplink of an active PON interface is faulty, the OLT automatically switches to a standby optical link, and notifies the ONU and requests switching by using a PST message through the standby optical link; and if the ONU detects that a downlink of an active PON interface is faulty, the ONU automatically switches to a standby optical link, and actively sends a PST message an OLT device to notify the OLT device that switching has been performed on the PON interface of the ONU and notify the OLT device of reasons of the switching, and to request switching.
Generally, an ONU merely maintains a set of OMCI MIB base inside, manages two access node interfaces (Access Node Interface, ANI) in this MIB base, cannot randomly perform an optical network terminal management and control interface (ONT Management and Control Interface, OMCI) management information base (Management Information Base, MIB) operation, and only can perform an OMCI operation on a current active PON interface, so as to avoid a problem of a MIB base operation conflict.